The cost of a 2 gig SD card is negligible. Sending this off to someone would incur shipping two ways, which to me would be insane. But to each his own.

I have another trick you can try. Format your SD card. Unzip the letterbomb thing that you've been using onto it. On the root directory, rename boot.elf to boot.elf.bak or delete it. Get a copy of the WiiMod dol, put it on the root directory of the card. Rename it to boot.elf. Then put the card in the wii, and attempt to launch via letterbomb. If you can get wiimod to load, post back and we can work something out.

Grab http://www.mediafire.com/?gvobket807cmlph. LEAVING EVERYTHING YOU HAVE CURRENTLY ON YOUR CARD, from this archive take ONLY THE WAD FOLDER and put it on your SD card. Put card in Wii, do letterbomb again, should load Wiimod. Go to wad manager, and install all the wads in this folder.